src/surf/maxmin.c

   1 /*      $Id$     */
   2
   3 /* Copyright (c) 2004 Arnaud Legrand. All rights reserved.                  */
   4
   5 /* This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the license (GNU LGPL) which comes with this package. */
   7
   8
   9 #include "xbt/sysdep.h"
  10 #include "xbt/error.h"
  11 #include "maxmin_private.h"
  12 #include <stdlib.h>
  13
  14 lmm_system_t lmm_system_new(void)
  15 {
  16   lmm_system_t l = NULL;
  17   s_lmm_variable_t var;
  18   s_lmm_constraint_t cnst;
  19
  20   l = xbt_new0(s_lmm_system_t, 1);
  21
  22   l->modified = 0;
  23   xbt_swag_init(&(l->variable_set),
  24                 xbt_swag_offset(var, variable_set_hookup));
  25   xbt_swag_init(&(l->constraint_set),
  26                 xbt_swag_offset(cnst, constraint_set_hookup));
  27
  28   xbt_swag_init(&(l->active_constraint_set),
  29                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  30
  31   xbt_swag_init(&(l->saturated_variable_set),
  32                 xbt_swag_offset(var, saturated_variable_set_hookup));
  33   xbt_swag_init(&(l->saturated_constraint_set),
  34                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  35
  36   return l;
  37 }
  38
  39 void lmm_system_free(lmm_system_t sys)
  40 {
  41   lmm_variable_t var = NULL;
  42   lmm_constraint_t cnst = NULL;
  43
  44   while ((var = extract_variable(sys)))
  45     lmm_var_free(sys, var);
  46
  47   while ((cnst = extract_constraint(sys)))
  48     lmm_cnst_free(sys, cnst);
  49
  50   xbt_free(sys);
  51 }
  52
  53 void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  54 {
  55   int i;
  56   lmm_element_t elem = NULL;
  57
  58   sys->modified = 1;
  59
  60   for (i = 0; i < var->cnsts_number; i++) {
  61     elem = &var->cnsts[i];
  62     xbt_swag_remove(elem, &(elem->constraint->element_set));
  63     if (xbt_swag_size(&(elem->constraint->element_set)))
  64       make_constraint_inactive(sys, elem->constraint);
  65   }
  66   var->cnsts_number = 0;
  67 }
  68
  69 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
  70 {
  71
  72   lmm_variable_disable(sys, var);
  73
  74   xbt_free(var->cnsts);
  75   xbt_free(var);
  76 }
  77
  78 static void lmm_cnst_free(lmm_system_t sys, lmm_constraint_t cnst)
  79 {
  80 /*   xbt_assert0(xbt_fifo_size(&(cnst->row)), */
  81 /*               "This list should be empty!"); */
  82   remove_active_constraint(sys, cnst);
  83   xbt_free(cnst);
  84 }
  85
  86 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
  87                                     xbt_maxmin_float_t bound_value)
  88 {
  89   lmm_constraint_t cnst = NULL;
  90   s_lmm_element_t elem;
  91
  92   cnst = xbt_new0(s_lmm_constraint_t, 1);
  93   cnst->id = id;
  94   xbt_swag_init(&(cnst->element_set),
  95                 xbt_swag_offset(elem, element_set_hookup));
  96   xbt_swag_init(&(cnst->active_element_set),
  97                 xbt_swag_offset(elem, active_element_set_hookup));
  98
  99   cnst->bound = bound_value;
 100   cnst->usage = 0;
 101   insert_constraint(sys, cnst);
 102
 103   return cnst;
 104 }
 105
 106 void lmm_constraint_free(lmm_system_t sys, lmm_constraint_t cnst)
 107 {
 108   remove_constraint(sys, cnst);
 109   lmm_cnst_free(sys, cnst);
 110 }
 111
 112 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 113                                 xbt_maxmin_float_t weight,
 114                                 xbt_maxmin_float_t bound,
 115                                 int number_of_constraints)
 116 {
 117   lmm_variable_t var = NULL;
 118
 119   var = xbt_new0(s_lmm_variable_t, 1);
 120   var->id = id;
 121   var->cnsts = xbt_new0(s_lmm_element_t, number_of_constraints);
 122   var->cnsts_size = number_of_constraints;
 123   /* var->cnsts_number = 0; *//* Useless because of the calloc  */
 124   var->weight = weight;
 125   var->bound = bound;
 126   var->value = -1;
 127   insert_variable(sys, var);
 128
 129   return var;
 130 }
 131
 132 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 133 {
 134   remove_variable(sys, var);
 135   lmm_var_free(sys, var);
 136 }
 137
 138 xbt_maxmin_float_t lmm_variable_getvalue(lmm_variable_t var)
 139 {
 140   return (var->value);
 141 }
 142
 143 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 144                 lmm_variable_t var, xbt_maxmin_float_t value)
 145 {
 146   lmm_element_t elem = NULL;
 147
 148   sys->modified = 1;
 149
 150   if (var->cnsts_number >= var->cnsts_size)
 151     abort();
 152
 153   elem = &(var->cnsts[var->cnsts_number++]);
 154
 155   elem->value = value;
 156   elem->constraint = cnst;
 157   elem->variable = var;
 158
 159   insert_elem_in_constraint(elem);
 160
 161   make_constraint_active(sys, cnst);
 162 }
 163
 164 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys, lmm_variable_t var, int num)
 165 {
 166   if(num<var->cnsts_number) return(var->cnsts[num].constraint);
 167   else return NULL;
 168 }
 169
 170 int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var)
 171 {
 172   return(var->cnsts_number);
 173 }
 174
 175 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys, lmm_constraint_t cnst,
 176                                      lmm_variable_t *var)
 177 {
 178   if(!(*var)) xbt_swag_getFirst(&(cnst->element_set));
 179   else *var=xbt_swag_getNext(*var,cnst->element_set.offset);
 180   return *var;
 181 }
 182
 183 void *lmm_constraint_id(lmm_constraint_t cnst)
 184 {
 185   return cnst->id;
 186 }
 187
 188 void *lmm_variable_id(lmm_variable_t var)
 189 {
 190   return var->id;
 191 }
 192
 193 static void saturated_constraints_update(lmm_system_t sys,
 194                                          lmm_constraint_t cnst,
 195                                          xbt_maxmin_float_t * min_usage)
 196 {
 197   lmm_constraint_t useless_cnst = NULL;
 198
 199   sys->modified = 1;
 200
 201   if (cnst->remaining <= 0)
 202     return;
 203   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 204     *min_usage = cnst->remaining / cnst->usage;
 205
 206     while ((useless_cnst = xbt_swag_getFirst(&(sys->saturated_constraint_set))))
 207       xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
 208
 209     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 210   } else if (*min_usage == cnst->remaining / cnst->usage) {
 211     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 212   }
 213 }
 214
 215 static void saturated_variables_update(lmm_system_t sys)
 216 {
 217   lmm_constraint_t cnst = NULL;
 218   xbt_swag_t cnst_list = NULL;
 219   lmm_element_t elem = NULL;
 220   xbt_swag_t elem_list = NULL;
 221
 222   sys->modified = 1;
 223
 224   cnst_list = &(sys->saturated_constraint_set);
 225   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 226 /*   xbt_swag_foreach(cnst, cnst_list) { */
 227     elem_list = &(cnst->active_element_set);
 228     xbt_swag_foreach(elem, elem_list)
 229         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 230     xbt_swag_remove(cnst, cnst_list);
 231   }
 232
 233 }
 234
 235 void lmm_solve(lmm_system_t sys)
 236 {
 237   lmm_variable_t var = NULL;
 238   lmm_constraint_t cnst = NULL;
 239   lmm_element_t elem = NULL;
 240   xbt_swag_t cnst_list = NULL;
 241   xbt_swag_t var_list = NULL;
 242   xbt_swag_t elem_list = NULL;
 243   xbt_maxmin_float_t min_usage = -1;
 244
 245   if(!(sys->modified)) return;
 246
 247   /* Init */
 248   var_list = &(sys->variable_set);
 249   xbt_swag_foreach(var, var_list) {
 250     var->value = -1;
 251   }
 252
 253
 254   /* Compute Usage and store the variables that reach the maximum */
 255
 256   cnst_list = &(sys->active_constraint_set);
 257   xbt_swag_foreach(cnst, cnst_list) {
 258     /* INIT */
 259     elem_list = &(cnst->element_set);
 260     cnst->remaining = cnst->bound;
 261     cnst->usage = 0;
 262     xbt_swag_foreach(elem, elem_list) {
 263       cnst->usage += elem->value / elem->variable->weight;
 264       insert_active_elem_in_constraint(elem);
 265     }
 266
 267     /* Saturated constraints update */
 268     saturated_constraints_update(sys, cnst, &min_usage);
 269   }
 270
 271   saturated_variables_update(sys);
 272
 273   /* Saturated variables update */
 274
 275   do {
 276     /* Fix the variables that have to be */
 277     var_list = &(sys->saturated_variable_set);
 278
 279
 280     xbt_swag_foreach(var, var_list) {
 281       /* First check if some of these variables have reach their upper
 282          bound and update min_usage accordingly. */
 283       if ((var->bound > 0) && (var->bound / var->weight < min_usage)) {
 284         min_usage = var->bound / var->weight;
 285       }
 286     }
 287
 288
 289     while ((var = xbt_swag_getFirst(var_list))) {
 290       int i;
 291
 292       var->value = min_usage / var->weight;
 293
 294       /* Update usage */
 295
 296       for (i = 0; i < var->cnsts_number; i++) {
 297         elem = &var->cnsts[i];
 298         cnst = elem->constraint;
 299         cnst->remaining -= elem->value * var->value;
 300         cnst->usage -= elem->value / var->weight;
 301         remove_active_elem_in_constraint(elem);
 302       }
 303       xbt_swag_remove(var, var_list);
 304     }
 305
 306     /* Find out which variables reach the maximum */
 307     cnst_list = &(sys->active_constraint_set);
 308     min_usage = -1;
 309     xbt_swag_foreach(cnst, cnst_list) {
 310       saturated_constraints_update(sys, cnst, &min_usage);
 311     }
 312     saturated_variables_update(sys);
 313
 314   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 315
 316   sys->modified = 0;
 317 }
 318
 319 /* Not a O(1) function */
 320
 321 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 322                 lmm_variable_t var, xbt_maxmin_float_t value)
 323 {
 324   int i;
 325   lmm_element_t elem = NULL;
 326
 327   sys->modified = 1;
 328   for (i = 0; i < var->cnsts_number; i++)
 329     if (var->cnsts[i].constraint == cnst) {
 330       elem->value = value;
 331       return;
 332     }
 333 }
 334
 335 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 336                                xbt_maxmin_float_t bound)
 337 {
 338   sys->modified = 1;
 339   var->bound = bound;
 340 }
 341
 342 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 343                                 xbt_maxmin_float_t weight)
 344 {
 345   sys->modified = 1;
 346   var->weight = weight;
 347 }
 348
 349 void lmm_update_constraint_bound(lmm_system_t sys, lmm_constraint_t cnst,
 350                                  xbt_maxmin_float_t bound)
 351 {
 352   sys->modified = 1;
 353   cnst->bound = bound;
 354 }
 355
 356 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 357 {
 358   return xbt_swag_belongs(cnst,&(sys->active_constraint_set));
 359 }
 360
 361
 362 /* void lmm_print(lmm_system_t sys) */
 363 /* { */
 364 /*   lmm_variable_t var = NULL; */
 365 /*   lmm_constraint_t cnst = NULL; */
 366 /*   lmm_element_t elem = NULL; */
 367 /*   xbt_swag_t cnst_list = NULL; */
 368 /*   xbt_swag_t var_list = NULL; */
 369 /*   xbt_swag_t elem_list = NULL; */
 370
 371 /*   var_list = &(sys->variable_set); */
 372 /*   xbt_swag_foreach(var, var_list) { */
 373 /*     printf("%s : {\n",var->id); */
 374 /*     printf("\t %s : {\n",var->id); */
 375 /*   } */
 376 /* } */